Vagrant and memcached documentation changes, and updates to install/ scripts.

Changes made in this branch:

Memcached
=========
Articles edited
-----------------
* doc/installation-makahiki-unix.rst (Added RHEL / CentOS installation instructions.)
* doc/configuration-system-administration-memcached.rst (Added enable/disable instructions.)

Vagrant
=======
Images added
---------------------
These appear in installation-makahiki-vagrant-eclipse.rst.
* doc/figs/vagrant-eclipse/debug_server_demo.png
* doc/figs/vagrant-eclipse/pydev_server_start_button.png
* doc/figs/vagrant-eclipse/remote_systems_explorer_ssh.png

Articles added
----------------------
This is the .txt documentation from vagrant/doc, split into multiple smaller articles.
* doc/installation-makahiki-vagrant.rst  (the index)
* doc/installation-makahiki-vagrant-configuration-memcached.rst
* doc/installation-makahiki-vagrant-configuration-vagrant.rst
* doc/installation-makahiki-vagrant-eclipse.rst
* doc/installation-makahiki-vagrant-quickstart.rst
* doc/installation-makahiki-vagrant-running-makahiki.rst
* doc/installation-makahiki-vagrant-troubleshooting.rst

Files removed
---------------------
* vagrant/doc/ubuntu_x86_vagrant_readme.txt: Removed because content is now in readthedocs
* vagrant/doc/vagrant_and_eclipse_readme.txt: Removed because content is now in readthedocs

Files moved
-----------------
* makahiki/vagrant/pydevd_demo.py --> makahiki/makahiki/remote-debugger-demo/pydevd_demo.py

Miscellaneous
-------------
* Documentation now tells users to copy **dist-packages** and **org.python.pydev_\<version-number\>** directories into makahiki/makahiki, instead of makahiki/vagrant
* Eclipse project imports the original .project and .pydevproject files from makahiki/makahiki
* .gitignore has been edited to ignore  **dist-packages** and **org.python.pydev_\<version-number\>** in makahiki/makahiki instead of makahiki/vagrant.

Install scripts
===============
These don't currently have readthedocs files because I was unsure whether they were being retained in the project or not.

Files updated
-------------
* ubuntu_installer.py: Removed need for every command to specify --arch parameter when some commands did not use it
* redhat_installer.py: Removed need for every command to specify --arch parameter when some commands did not use it
* redhat/dependency_redhat.py: Added x86 support, fixed symbolic link creation for libz.so and libjpeg.so